597 is only unit left    Have for sale 2 Humminbird fish finders.   Although these are legacy units and no longer manufactured, they are in excellent condition, with the latest software available from Humminbird website installed.  SD card reader works on both units, no map chip included with purchase.  Each unit also includes a black UC 3 snap-on hard cover.     Units are compatible with XNT 9 20 Transducer or XI 9 20 Ice Ducers.   Both units have been us